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What caribou do, without you: Fortymile herd outfitted with cameras

If a caribou munches lichen in the woods, and no one’s around to hear it, does it make a sound?

If a caribou munches lichen in the woods, and no one’s around to hear it, does it make a sound?

Of course it does! What, you think nature just hits pause when people aren’t around and nothing happens without us? That’s not how nature works, as biologists well know: observing wildlife in their natural habitat, doing what they do everyday when people aren’t looking– without impacting that behaviour–with their presence is one of the biggest challenges biologists face when they’re gathering data in the field.

This is especially true of barren ground caribou, Yukon’s arguably most beloved, iconic–and, when it comes to habitat and harvest management, politically fraught– large mammal. Unlike boreal caribou, which inhabit much smaller and more predictable ranges, barren ground ‘bou make tremendous annual migrations, thousands of kilometers long, gathering together in huge groups to travel, mate and calve, meaning researchers who want to study them have to do so over unimaginably large swaths of difficult sub-arctic terrain.

To get around this and get better — and more intimate — data, biologists from Yukon and Alaska took a novel approach — they basically go-pro’d the caribou.

Caribou research has often utilized GPS collars, which track an animal’s movements, but these collars were also fitted with cameras to 15 cows from the Fortymile Caribou Herd– a politically and culturally sensitive herd co-managed between Alaska, Yukon and the Trʼondëk Hwëchʼin, which was very nearly extirpated from its home range and has only recovered in recent decades thanks to disciplined trilateral conservation efforts. The collars were programmed to only stay on for a set amount of time, at which point they fell off and were recovered via their GPS signal by plane, says Jim Herriges, a wildlife biologist with the Alaska Bureau of Land Management (BLM) who worked on the study.

This minimally invasive technique allowed researchers to collect visual data from the caribou’s point of view, kind of like a POV video game. From this perspective, they watch caribou do all the things caribou do–eat, mate, sleep, seek refuge from bugs and predators–even die and become food for other members of the food chain, such as ravens and bears.

Working with the camera data was a fun twist to her research, said Libby Ehlers, a Ph.D. student at the University of Montana, who had initially thought she would be using standard GPS data. Instead, she wound up with nearly 200,000 videos collected during the summers of 2018 and 2019, a whopping amount of incredibly detailed, up-close-and-personal data.

Working with a team of volunteers and an assistant, Ehlers selected 18,000 videos as a random subset to make that data easier to manage and set about watching them; through the videos, Ehlers was able to break the caribou’s behaviors into five distinct categories: eating, ruminating, traveling, stationary awake and napping.

Elhers found that caribou spend about 45 per cent of their time eating and another 25 per cent of that time ruminating–rumination is the part of the digestion process for all even-toed ungulates, of which caribou are included—and about 15 per cent of their time traveling. There were also a bunch of other activities, such as drinking water, licking salt or other minerals, or just “other more rare behaviours” which comprised about five per cent of the caribou’s time “budget.”

One of the neat things that came out of the study for him, says Herriges, is what and how much of certain things the caribou in this herd were eating. A pre-study fecal pellet analysis (looking at caribou poop to see what they were eating) showed the caribou were eating a lot more lichen than expected. The study confirmed this–they were eating a lot of lichen, which is a relatively low-quality forage–but also more shrubs and leaves than previously thought, probably because those things are more readily absorbed and don’t survive the digest tract, making them harder to quantify through feces.

Caribou also love mushrooms, says Herriges, especially boletes, and you can see them chowing down on them in the videos.

“Mushrooms are just big chunks of readily digestible protein (for caribou), and they really go for them,” he said.

Aside from their love of fungi, you can also see caribou actively determining which mushrooms are good for them and which ones aren’t. In one video, he said, you could see a caribou spot a tasty mushroom snack and head right for it, “really going at it” and wolfing it down. In another, you could see a caribou approach a mushroom, sniff it, and walk away–it was an aminta, which are often poisonous, although can be edible to caribou at certain life stages.

“These are just some of the interesting things you can see caribou do in these videos,” he said.

Lori Fox is a writer and journalist based in Whitehorse. Their first book, This Has Always Been A War, will be released on May 3.